The Pearl River is one of China’s large rivers, the second-largest river and the fourth-longest river in China. Its unique geography, landform, and climate conditions create unique fluvial geomorphological processes. Affected by human activities and climate change, the fluvial geomorphological processes in the Pearl River Basin have undergone significant changes in recent decades, seriously affecting the river’s sustainable development. This paper critically reviews changes in fluvial geomorphological processes and analyzes influencing factors in the Pearl River Basin with a focus on possibilities for policy overhaul and strategic adjustments.

Land use/cover change (LUCC) is a vital aspect representing global change and humans’ impact on Earth’s surface. This study utilized the ESRI Land Cover 2020 and China Land Cover Dataset (CLCD), along with historical imagery from Google Earth, to develop a method for the assessment of land use data quality. Based on the assessment, the CLCD was updated to generate an improved Re-CLCD for the Pan-Pearl River Basin (PPRB) from 1985 to 2020, and to analyze LUCC in the PPRB over the past 35 years. The results indicate the following: (1) Among the seven land uses, built-up land experienced the most dramatic change, followed by cropland, forestland, grassland, shrubland, waterbody, and bare land, with notable increases in built-up land and forestland, and rapid decreases in cropland, grassland, and shrubland. (2) The magnitude of land use changed very widely, with the highest change in the Pearl River Delta, followed by small coastal river basins in southern Guangdong and western Guangxi, the Dongjiang River Basin, the Hanjiang River Basin, the Xijiang River Basin, the Beijiang River Basin, and lastly, Hainan Island. (3) The largest increase happened in built-up land, with a total increase of 12,184 km², mainly due to the occupation of cropland and forestland, corresponding to the highest decrease in cropland, with a net loss of 10,435 km², which was primarily converted to forestland and built-up land. The study results are valuable in providing a scientific basis for policy overhaul regarding land resources and management to safeguard ecological balance and promote sustainable development in the Pan-Pearl River Basin.

The changes in land use/cover are essential aspects of studying the impact of human activities on the Earth's surface and global transformations. In this study, utilizing the ESRI Global Land Cover data (ESRI land cover 2020) and the China Land Cover Data (CLCD), along with historical imagery from Google Earth, a comparative analysis scheme for land use classification results was designed. The CLCD dataset was updated, leading to the creation of a land use dataset for the Pan-Pearl River Basin spanning from 1985 to 2020. This dataset was then employed for the analysis of land use changes in the Pan-Pearl River Basin over the past 35 years.The results indicate:(1) Among the seven land use types, the most significant changes in area occurred in the following order: build -up land, cropland, forest land, grassland, shrubland, waterbody, and barren. Notably, there was a substantial increase in the areas of build-up land and forest land, while cropland, grassland, and shrubland experienced significant decreases. The waterbody’area showed a slight overall increase trend.(2) The major land use types undergoing changes varied among sub-basins, with the intensity of land use change ranked as follows: Pearl River Delta region(1.9%) > Coastal rivers in southern Guangdong and western Guangxi(0.20%) > Dongjiang River Basin(0.13%) > Hanjiang River Basin(0.12%) > Xijiang River Basin(0.10%) > Beijiang River Basin(0.08%) > Hainan Island region(0.02%).(3) Within the sub-basins of the Pan-Pearl River Basin, the most significant increase was observed in the area of built-up land, exhibiting a continuous expansion trend with a total increase of 12184 km2. This increase was primarily due to the conversion of cropland, forest land, and waterbody. The most significant decrease occurred in cropland, with a total reduction of 10435 km2, mainly transitioning to built-up land and forest land. The phenomenon of built-up land encroaching on cropland was particularly prominent, especially in the Pearl River Delta region. Forest land also showed a decreasing trend, mainly attributed to cultivation and the encroachment of built-up land. The reduction in grassland area was more pronounced in the Xijiang River Basin, primarily transforming into forest land, cropland, and built-up land. The study reveals that the rapid development of socio-economics and industry, coupled with an increase in residents' consumption levels, serves as the primary driving force behind land use changes in the Pan-Pearl River Basin. Additionally, land use and management policies play a crucial role as driving factors in the region's land use changes. This research aims to provide a scientific basis for formulating policies related to the region's land resources and land management, holding significant importance for preserving ecological balance and fostering sustainable development in the basin.